In the field of semiconductor device manufacturing, microfabrication of a semiconductor substrate, such as a silicon wafer, is performed at times by plasma etching, which is one type of dry etching. During this etching process, a member inside a semiconductor device manufacturing apparatus that is exposed to reactive plasma may be subject to erosion (damage) and generate particles. Deposition of the generated particles on the semiconductor substrate may make it difficult to perform microfabrication as designed or cause contamination of the semiconductor substrate by elements contained in the particles. A thermal spray coating containing a rare earth element is therefore conventionally provided on a member exposed to reactive plasma during the etching process to protect the member from plasma erosion (see, for example, Patent Document 1).
However, even with a thermal spray coating containing a rare earth element, the generation of particles cannot be suppressed completely. In order to minimize the detrimental effects due to particles as much as possible, it is important first of all to reduce the number of particles deposited on the semiconductor substrate, and for this purpose, it is effective to reduce the size of particles generated when a thermal spray coating is subject to plasma erosion. This is because particles of small size are readily subject to erosion by the reactive plasma while being suspended in the etching process and eventually made to disappear by being gasified or are readily discharged to the exterior by being carried by a gas flow inside the semiconductor device manufacturing apparatus and are thereby prevented from depositing on the semiconductor substrate.